Geometry of Fluid Interfaces
AG Prof. Dr. Ralf Seemann

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Artificial Cascade Signaling

In the previous years, we developed and optimized a microfluidic platform that enables fabrication of lipid bilayers and testing their properties. This microfluidic platform is used to reconstitute proteins into a model membrane and to realize an artificial cascade signaling.

Together with our colleague Albrecht Ott (Experimental Physics) we produce photo-sensible bacterial rhodopsin protein (Archaerhodopsin-3) via a cell-free expression system and injected these proteins around a bilayer that is fabricated in a microfluidic setup. Using this strategy functional ion channels can be inserted in a bilayer as can be demonstrated by measuring electrical conductivity. Interestingly, an impressive and reversible protein conductivity is observed when exposing the bilayer to light (λ≈ 530 nm) (Fig. 1a-c).

Fig.1:: (a) DPhPC/DOPC bilayer separates pure buffer phase in the upper channel from fluorescent GFP-Archaerhodopsin-3 monomers present in the bottom channel [1]. (d) Current measurements across a DPhPC/DOPC bilayer demonstrating the oligomerization of functional rhodopsin channels, with the corresponding pore size distribution [2]. e) Effect on light exposition (λ≈ 530 nm) on the bilayer conductivity.

Group members on this project: Dr. Jean-Baptiste Fleury, Navid Khangoli, Prof. Dr. Ralf Seemann

Internal collaborations: Albrecht Ott (Saarland University, Experimental Physics)

Funding: